Recently, a lady contacted our office about to have a horticultural stroke over a short paragraph I wrote about lawns in my “Dealing with Freeze Damage on Plants” notes on my Greg Grant Gardens Facebook back in February and March. Who would think that six sentences could cause such indignation and outrage?
St. Augustine and Centipede lawns: There will possibly be dead areas and freeze damage. Mow as normal; but avoid pre-emergent herbicides which can damage injured grass. Do not fertilize until nights are warmer in mid-April and do not water until June, July, and August, once per week, one inch per application. Watering in the spring contributes to gray leaf spot and brown patch. Most folks water too often and cause their own problems. Bermudagrass and zoysiagrass are more-cold hardy and should be just fine.
I’ll be the first to admit that I’m not technically a turfgrass expert or certified turfgrass professional. In the past, I was however certified as a Master Texas Certified Nursery Professional, a Texas Master Gardener, and have a Masters’ Degree in Horticulture. I also worked at the Texas A&M Turfgrass Laboratory in College Station when I was in school and also at the LSU Turfgrass Laboratory in Baton Rouge. Still yet, I’ve mowed and maintained lawns all my life, first motivated by extra cash, and now by a stick wielding Cajun.
If you want lawn advice and instructions from true professionals, you need to follow “AggieTurf: Texas A&M Turfgrass Program” on Facebook and take advantage of our Texas A&M AgriLife Extension Service “Aggie Turf” web page at aggieturf.tamu.edu where there is a plethora of lawn care publications/fact sheets.
My type of lawn care is a combination of me being both a horticulturist and a naturalist who doesn’t have the time or temperament to nurse and spoon feed a lawn. Don’t get me wrong. Like most Americans, I love lawns. I even like to mow them. It’s one of the few things you can look back on (literally) and say “That was ragged, but I made it right.” I suppose it’s the same reason I enjoy plowing a garden.
I do not however believe in wasting precious water and expensive fertilizer, or exposing ourselves, children, pets, birds, bees, and butterflies to insecticides, fungicides, and herbicides based on scheduled usage, which in many cases treats the symptom not the root cause. If you’ve ever read Rachel Carson’s Silent Spring (1962, Houghton Mifflin), own a multitude of bluebird nest boxes like I do, or have poisoned your wife’s kitten accidentally, like I think I may have, you’ll rethink ever using pesticides in your lawn or garden again.
I knew from past experience that there could be damage this year on St. Augustine and centipede (neither cold-hardy in the upper two-thirds of the U.S.) So I asked Dr. Becky Bowling, PhD, one of our Texas A&M turfgrass specialists, for her expert advice on using pre-emergent herbicides on potentially freeze damaged lawns. Her advice was:
As a general rule of thumb, preemergence herbicides are intended for healthy lawns. Those that have potentially experienced significant winter injury/kill are not going to be great candidates for broadcast applications of any herbicide – PRE or POST until they have had an opportunity to recover. Particularly in the case of preemergence herbicides available to the general public for home lawns, these products can be root inhibiting and may impede recovery. My recommendation is to refrain from making any broadcast herbicide applications on turfgrass lawns until they have demonstrated sufficient recovery and green-up. In the meantime, homeowners should focus on mechanical control and spot treatment.
I frequently see “clubbed roots” on St. Augustine lawns due to damage from preemergent herbicides. It generally adds up to homeowners not following label directions and applying too much or to lawn care services over-applying both post and pre-emergent herbicides. One lawn I looked at was literally clinging to life with severely damaged roots from the lawn care company using three different herbicides to attempt to both control and prevent weeds. The reason for all the weeds was because the lawn was very thin due to both shade and summer drought. The neighbor however had a fine lawn and had used nothing but a mower on his. Most folks have the mistaken impression that weeds invade and “take over” lawns when the weeds are actually just opportunists taking advantage of bare soil and sunlight. All you have to do is plow a garden, don’t mulch, and then wait and watch. I learned these tell-tale clubbed roots while conducted preemergent herbicide rates research at the Texas A&M Turfgrass Lab years ago. And for the record, I don’t use pre-emergent herbicides on my lawns or ever intend too.
As far as fertilizing goes, since our Southern warm season turfgrasses are all a bit sub-tropical in origin, experts have always recommended waiting to fertilize until the night and soil temperatures are warm and the grass itself is actively growing. We often say “Wait until you’ve mowed the lawn (not the weeds) at least three times before fertilizing. Fertilizing too early actually wastes expensive fertilizer by feeding the cool season weeds or by having it leached away before the warm season turf is able to use it. When I started in Extension years ago, some of our publications recommended fertilizing 6-8 times a year! I myself eventually backed off to three times a year (spring, summer, and fall) on bermudagrass, two times a year on St. Augustine and zoysia (spring and fall), and one time a year on centipede) (spring). But after a lifetime of seeing perfectly fine lawns, trees, shrubs, roses, bulbs, etc., guess how many times I fertilize my lawn? Generally not at all, unless I’m trying to speed up establishment or thicken up a cool season lawn during fall, winter, or early spring, that has been overseeded with perennial rye. Having a good lawn is basic horticulture. It’s more about sunlight, frequent mowing, limited foot traffic, summer irrigation during droughts, and not “killing with kindness,” which brings us to sprinkler systems.
The majority of the St. Augustine grass problems I have to hear about and diagnose are in lawns that have sprinkler systems. The most common problem is running it during fall, winter, and spring when we have adequate soil moisture and don’t need supplemental water. Have you ever heard “April showers bring May flowers?” All fungus diseases, including brown patch and gray leaf spot, begin with a film of water on the leaf. These diseases are prevalent enough during our rainy periods without exacerbating the problem by watering too frequently or during rainy periods. Watering more than one time per week is ridiculous and leads to shallow roots and increased disease. And since I’ve seen (and photographed) many perfectly good lawns that have neither been fertilized nor irrigated, I honestly think that watering any more than once per week during June, July, and August (minus rainfall), one inch per application, is ridiculous and wasteful. I can’t imagine how many exponential millions of gallons of our limited water supplies would be saved if those with sprinkler systems would only water 12 times per year during those months only. One again, I’ll confess that I don’t have a sprinkler system, don’t intend to have a sprinkler system, and rarely irrigate my lawn, even 12 times per year. I do however keep it mowed and looking nice.
And when it comes to insecticides, I never treat my entire lawn. The only insects I treat are fire ants and I do individual mound treatment only. Remember, the reason diazinon and dursban were banned from homeowners was because of bird kills, nerve damage, and water supply contamination due to wide and indiscriminate use. We need to seriously rethink American lawns, including what we put in them and what we put on them. Monoculture has always been a tough row to hoe.
The way most Americans think about and treat their lawns isn’t sustainable and isn’t healthy for them or the environment. I have one small zoysia lawn that I try and keep weed free, otherwise I let anything grow that wants to and can survive once a week mowing. Personally, I think it’s a privilege to have Dutch clover, spring beauty, and crow poison blooming and teaming with bees and butterflies throughout the rest of my “lawn” between mowing. Birds, bees, and butterflies need all the help they can get and I think homeowners should be part of the solution, not part of the problem.
Anyone that tells you a lawn HAS to be treated with insecticides, fungicides, herbicides, and fertilizers is either obsessive compulsive or selling the products. I’ll save my money for pansies, perennials, pines, potatoes, pots, potting soil, poultry, and plenty of other stuff.